Method for gridding two-dimensional seismic reflection data to obtain a three-dimensional volume

Abstract

The application provides a method for obtaining a three-dimensional body by gridding two-dimensional seismic reflection data, and belongs to the field of seismic data processing. The method converts two-dimensional survey lines into a three-dimensional data body uniformly distributed in space by means of a virtual grid rotation technique, and makes subsequent data processing no longer limited to one direction. Specifically, the latitude and longitude coordinates of each discrete reflection data are obtained and converted into UTM projection rectangular coordinate values, and the coordinate value of the minimum longitude point is determined. The optimal azimuth angle of the grid is calculated according to the planar distribution characteristics of the discrete points, and the grid spacing along the azimuth angle direction and the direction perpendicular to the azimuth angle is determined. The grid is rotated to a three-dimensional grid direction, and the coordinate of the minimum longitude value point after rotation is extended outward by half the grid spacing. The coordinate of this point is used as the base point of the grid. All coordinate points are rotated in the same way, the data falling into the same grid are superimposed, the coordinate number of each point in the grid is calculated, and a three-dimensional data body is obtained accordingly.

Description

Technical Field

[0001] This application proposes a method for obtaining a three-dimensional data volume based on dense two-dimensional seismic reflection data with uneven spatial distribution through rapid gridding, which belongs to the field of seismic data processing. Background Technology

[0002] Two-dimensional (2D) seismic data is typically acquired along a single survey line or a series of parallel lines, which may lead to inaccurate interpretation of geological features and subsurface structural depth. In contrast, 3D seismic data offers better vertical resolution and more accurate migration positioning, facilitating more convenient and intuitive tasks such as stratigraphic visualization, fault interpretation, coherence analysis, and reservoir description, and enabling comprehensive analysis of geological structures. However, in the early stages of exploration, 3D seismic exploration is currently not feasible in areas with complex topography and marine conditions due to exploration risks and costs, while 2D seismic exploration struggles to meet the requirements for regularization. Therefore, to improve exploration accuracy, it is necessary to utilize spatially non-uniform 2D seismic data to enhance the reliability of exploration area evaluation and the selection of oil, gas, and hydrate reservoirs. One effective method is virtual 3D seismic technology.

[0003] Existing virtual 3D seismic technology converts 2D seismic lines into corresponding 3D seismic data according to the arrangement of a 3D observation system, and merges the 2D databases to create a virtual 3D database. This allows for the application of 3D data processing and interpretation techniques. In actual seismic exploration, for specific geological targets, such as seafloor heat flow, shallow gas and fault development, and bedrock depth, small-spacing receivers or seafloor ARV acquisition methods are used. These methods result in sparse seismic lines but dense sampling, uneven spatial distribution, and irregular variations in line length, azimuth, and coverage frequency. Commonly used virtual 3D seismic methods are typically implemented using software such as Jason, which has certain limitations.

[0004] There is an urgent need for a versatile, efficient, and easy-to-implement 3D meshing scheme for seismic data to improve the imaging quality and interpretability of seismic data. Therefore, this application is hereby submitted. Summary of the Invention

[0005] The method for obtaining a three-dimensional volume from two-dimensional seismic reflection data proposed in this application aims to solve the problems existing in the prior art by constructing a virtual grid through rotation. This method aims to make the calculation process unaffected by the azimuth angle and significantly simplify the calculation process of determining the relationship between scattered points and grid points. In this way, the two-dimensional survey line is transformed into a spatially uniformly distributed three-dimensional data volume, and the subsequent data processing is no longer limited to one direction. This achieves the goal of ensuring that the results are more consistent with geological laws and more convenient for geological interpretation.

[0006] Therefore, the method for obtaining a three-dimensional volume from two-dimensional seismic reflection data by gridding as described in this application involves obtaining the latitude and longitude coordinates of each discrete reflection data and converting them into UTM projected rectangular coordinates to determine the coordinates of the point with the minimum longitude; calculating the optimal azimuth angle of the grid based on the planar distribution characteristics of the discrete points, and determining the grid spacing along the azimuth direction and perpendicular to the azimuth direction; rotating the grid to the three-dimensional grid direction, and extending the coordinates of the point with the minimum longitude value outward by half a grid spacing, using the coordinates of this point as the base point of the grid; performing the same rotation on all coordinate points, superimposing the data falling within the same grid, and then calculating the coordinate number of each point in the grid to obtain the three-dimensional data volume.

[0007] The implementation steps include the following:

[0008] Step (1): Determine the projection zone and the longitude of the central meridian based on the latitude and longitude coordinates of the reflection points within the work area;

[0009] Step (2): Calculate the UTM projection coordinates of the reflection points of each two-dimensional survey line using coordinate projection;

[0010] Step (3): Calculate and determine the azimuth angle of each two-dimensional survey line based on the UTM projection coordinates; the average azimuth angle of all two-dimensional survey lines that is less than or equal to the median of the azimuth variance is taken as the azimuth angle of the two-dimensional grid.

[0011] Step (4): Calculate the azimuth angle of the two-dimensional grid;

[0012] First, calculate the average value of the original azimuth angle for each survey line. :

[0013] (1)

[0014] Then, calculate the variance of the azimuth angle. :

[0015] (2)

[0016] Step (5): Rotate the survey line from the azimuth of the two-dimensional grid to the azimuth of the three-dimensional grid using coordinate rotation;

[0017] Step (6): Determine the parameters of the three-dimensional data volume observation system;

[0018] UTM projection coordinates of all reflection points Perform a coordinate rotation, the rotation angle being the azimuth angle of the 3D mesh. To obtain the rotated coordinates :

[0019] (3)

[0020] (4)

[0021] in,( , ) is the minimum longitude coordinate ( , The projected coordinates after projection transformation. and These represent the desired 3D grid spacing for the output;

[0022] Step (7): Data overlay within the same 3D grid;

[0023] Step (8): Calculate the 3D mesh number of all reflection points;

[0024] Based on the relationship between the coordinates of the reflection points after superposition and the coordinates of the mesh origin, calculate the coordinate number of each reflection point in the 3D mesh. :

[0025] (5)

[0026] (6)

[0027] Step (9): Sort the coordinates of all reflection points after superposition according to the grid number to obtain a three-dimensional meshed three-dimensional data volume.

[0028] In step (1), input two-dimensional seismic reflection data located in the work area. The data includes track heads, survey line spacing and track spacing. The track heads contain spatial coordinate information of the reflection points.

[0029] Obtain the latitude and longitude coordinates of all two-dimensional survey lines. ( Determine the minimum longitude coordinates. Add 180 to this value, divide by 6, round down, and add 1 to obtain the longitude of the central meridian in the coordinate projection. :

[0030] (7)

[0031] Step (2) involves converting the latitude and longitude coordinates of all reflection points into UTM projection coordinates. ( If the latitude value of the UTM projection coordinates is less than zero, then the work area is located in the Southern Hemisphere, and its latitude value calculation result needs to be increased by 10,000,000; otherwise, the work area is located in the Northern Hemisphere.

[0032] Step (3) includes fitting the original azimuth angle of each two-dimensional survey line using the least squares principle, calculating the variance of the azimuth angle and sorting them from smallest to largest, determining the median of the azimuth angle variance, and selecting the average value of the azimuth angles with variances less than or equal to the median as the azimuth angle of the two-dimensional grid to avoid interference from data with large azimuth angle offsets; and based on the UTM projection coordinate values... The original azimuth angle of each two-dimensional survey line is fitted using the least squares principle. The azimuth angle calculation process is as follows:

[0033] Step (3.1): Calculate all and and and ;

[0034] Step (3.2): Calculate all and and and ;

[0035] Step (3.3): Calculate the slope of the line. :

[0036] (8)

[0037] Step (3.4): Calculate the azimuth angle ( ):

[0038] (9)

[0039] Step (5) includes sorting the azimuth variances of each survey line from smallest to largest, and selecting the average azimuth variances of the top 50% as the azimuth variances of the three-dimensional grid. When the survey line is oriented northwest to southeast. Take the positive value, when the direction is southwest to northeast. Take the negative value;

[0040] Step (7) includes calculating the origin of the three-dimensional mesh and determining the desired output three-dimensional mesh spacing. and The minimum longitude coordinates ( , Projected coordinates after projection transformation , Expand outward by half and The origin of the three-dimensional mesh is taken as the first one. ;

[0041] Among them, when When the value is positive, the origin of the 3D mesh is taken as... Conversely, the origin of the 3D mesh is taken as... ;

[0042] The data falling into each 3D grid is checked. If there are multiple data in a grid, these data are superimposed. The superimposed result is used as the data of the grid center point. The coordinates of the superimposed result are taken as the coordinates of the grid center point.

[0043] Assume the first Within each grid The data point, the first The distance between each data point and the center point of the grid is... Then the data within this grid is:

[0044] (10)

[0045] In step (9), the parameters of the three-dimensional data volume observation system include the coordinates of the corner points of the work area, the spacing between the main survey lines, the spacing between the connecting survey lines, and the track spacing.

[0046] This application proposes an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: when the processor executes the program, it implements the above-mentioned method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data.

[0047] This application proposes a computer-readable storage medium storing a computer program, characterized in that: when the computer program is executed, it can realize the above-mentioned method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data.

[0048] In summary, this application has the following advantages and beneficial effects compared with the prior art:

[0049] 1. This application constructs a virtual three-dimensional mesh through azimuth angle calculation and coordinate rotation, which can effectively rotate a spatially uneven two-dimensional observation system to any azimuth angle. The calculation process is not affected by the original azimuth angle, which greatly simplifies the calculation of the relationship between scattered points and grid points, and the calculation results are more accurate.

[0050] 2. After converting the two-dimensional survey lines into a spatially uniformly distributed three-dimensional data volume, the subsequent data processing is no longer limited to one direction, ensuring that the results are more consistent with geological laws and more convenient for geological interpretation.

[0051] 3. This application only requires calculation of spatial coordinates, which is more efficient and more suitable for densely sampled seismic data and dense discrete point data related to geodesy (such as gravity and magnetism). Attached Figure Description

[0052] The implementation process of the present application will now be further explained and illustrated with reference to the following figures.

[0053] Figure 1 This is a flowchart of the method for obtaining a three-dimensional volume from two-dimensional seismic reflection data by meshing, as described in this application.

[0054] Figure 2 A schematic diagram showing the location of the common center point of dense two-dimensional seismic reflection data with uneven spatial distribution; Figure 2 The middle arrow points to the direction of the azimuth of the survey line in the work area;

[0055] Figure 3 A schematic diagram for calculating the azimuth of a portion of the survey line; Figure 3 Solid lines represent two-dimensional survey lines, and dashed arrows indicate the azimuth direction of the corresponding survey line;

[0056] Figure 4 This is a schematic diagram of the rotation of the azimuth angle of the survey line; Figure 4 middle This is the difference between the azimuth angle of the 3D mesh and the azimuth angle of the 2D mesh, i.e., the rotation azimuth angle;

[0057] Figure 5 A schematic diagram illustrating the effect of interactive orientation determination for 3D surface meshes;

[0058] Figure 6 This is a two-dimensional survey profile of a certain work area;

[0059] Figure 7 for Figure 6 The corresponding survey line profile in the 3D data volume after meshing; Detailed Implementation

[0060] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described below in conjunction with the accompanying drawings and embodiments. Many specific details are set forth in the following description to provide a thorough understanding of this application; however, this application may be implemented in other ways than those described herein, and therefore, this application is not limited to the specific embodiments disclosed below.

[0061] Example 1, such as Figures 1 to 7 As shown, this application proposes a method for obtaining a three-dimensional volume from two-dimensional seismic reflection data by gridding. The method involves acquiring the latitude and longitude coordinates of each discrete reflection data point and converting them into UTM projected rectangular coordinates, determining the coordinates of the point with the minimum longitude; calculating the optimal azimuth angle of the grid based on the planar distribution characteristics of the discrete points, and determining the grid spacing along the azimuth direction and perpendicular to the azimuth direction; rotating the grid to the three-dimensional grid direction, and extending the coordinates of the point with the minimum longitude value outwards by half a grid spacing, using the coordinates of this point as the base point of the grid; performing the same rotation on all coordinate points, superimposing the data falling within the same grid, and then calculating the coordinate number of each point in the grid to obtain the three-dimensional data volume.

[0062] The method includes the following implementation steps:

[0063] Step (1): Determine the projection zone and the longitude of the central meridian based on the latitude and longitude coordinates of the reflection points within the work area;

[0064] Input two-dimensional seismic reflection data located within the work area. The data includes track heads, survey line spacing, and track spacing. Track heads contain spatial coordinate information of reflection points.

[0065] Obtain the latitude and longitude coordinates of all two-dimensional survey lines. ( Determine the minimum longitude coordinates. Add 180 to this value, divide by 6, round down, and add 1 to obtain the longitude of the central meridian in the coordinate projection. :

[0066] (1)

[0067] Step (2): Calculate the UTM projection coordinates of the reflection points of each two-dimensional survey line using coordinate projection;

[0068] Convert the latitude and longitude coordinates of all reflection points to UTM projected coordinates ( );

[0069] If the latitude value of the UTM projection coordinates is less than zero, then the work area is located in the Southern Hemisphere, and its latitude value calculation result needs to be increased by 10,000,000; otherwise, the work area is located in the Northern Hemisphere.

[0070] Step (3): Calculate and determine the azimuth angle of each two-dimensional survey line based on the UTM projection coordinates;

[0071] The average azimuth of all two-dimensional survey lines that is less than or equal to the median of the azimuth variance is taken as the azimuth of the two-dimensional grid.

[0072] Specifically, the original azimuth angle of each two-dimensional survey line is fitted using the least squares principle, the variance of the azimuth angle is calculated and sorted from smallest to largest, the median of the azimuth angle variance is determined, and the average value of the azimuth angles with variance less than or equal to the median is selected as the azimuth angle of the two-dimensional grid to avoid interference from data with large azimuth angle offsets.

[0073] Based on UTM projection coordinates The original azimuth angle of each two-dimensional survey line is fitted using the least squares principle. The azimuth angle calculation process is as follows:

[0074] Step (3.1): Calculate all and and and ;

[0075] Step (3.2): Calculate all and and and ;

[0076] Step (3.3): Calculate the slope of the line. :

[0077] (2)

[0078] Step (3.4): Calculate the azimuth angle ( ):

[0079] (3)

[0080] Step (4): Calculate the azimuth angle of the two-dimensional grid;

[0081] First, calculate the average value of the original azimuth angle for each survey line. :

[0082] (4)

[0083] Then, calculate the variance of the azimuth angle. :

[0084] (5)

[0085] Step (5): Rotate the survey line from the azimuth of the two-dimensional grid to the azimuth of the three-dimensional grid using coordinate rotation;

[0086] Sort the azimuth variances of each survey line from smallest to largest, and select the average azimuth variance of the top 50% as the azimuth of the 3D mesh. ;

[0087] To avoid interference from data with large azimuth offsets, when the survey line azimuth is NW-SEM... Take the positive value, when the direction is southwest to northeast. Take the negative value;

[0088] Step (6): Determine the parameters of the three-dimensional data volume observation system;

[0089] UTM projection coordinates of all reflection points Perform a coordinate rotation, the rotation angle being the azimuth angle of the 3D mesh. To obtain the rotated coordinates :

[0090] (6)

[0091] (7)

[0092] in,( , ) is the minimum longitude coordinate ( , The projected coordinates after projection transformation. and These represent the desired 3D grid spacing for the output;

[0093] Step (7): Data overlay within the same 3D grid;

[0094] Calculate the origin of the 3D mesh, based on the desired output 3D mesh spacing. and The minimum longitude coordinates ( , Projected coordinates after projection transformation , Expand outward by half and The origin of the three-dimensional mesh is taken as the first one. ;

[0095] Among them, when When the value is positive, the origin of the 3D mesh is taken as... Conversely, the origin of the 3D mesh is taken as... ;

[0096] The data falling into each 3D grid is checked. If there are multiple data in a grid, these data are superimposed. The superimposed result is used as the data of the grid center point. The coordinates of the superimposed result are taken as the coordinates of the grid center point.

[0097] Assume the first Within each grid The data point, the first The distance between each data point and the center point of the grid is... Then the data within this grid is:

[0098] (8)

[0099] Step (8): Calculate the 3D mesh number of all reflection points;

[0100] Based on the relationship between the coordinates of the reflection points after superposition and the coordinates of the mesh origin, calculate the coordinate number of each reflection point in the 3D mesh. :

[0101] (9)

[0102] (10)

[0103] Step (9): Sort the coordinates of all reflection points after superposition according to the grid number to obtain a three-dimensional meshed three-dimensional data volume;

[0104] The parameters of the three-dimensional data volume observation system include the coordinates of the corner points of the work area, the spacing between the main survey lines, the spacing between the connecting survey lines, and the track spacing.

[0105] like Figure 7 As shown, Figure 7 for Figure 6 In the 3D data volume after rapid gridding of medium- and two-dimensional seismic reflection data, the corresponding survey line profile in the figure shows an improved signal-to-noise ratio, especially in the area circled by the ellipse, where the signal-to-noise ratio is significantly improved, and weak reflection phase axes are imaged more clearly.

[0106] This application also proposes a novel electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the above-mentioned method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data.

[0107] This application also proposes a novel computer-readable storage medium storing a computer program that, when executed, enables the above-described method for obtaining a three-dimensional volume from two-dimensional seismic reflection data through gridding.

[0108] As described above, similar technical solutions can be derived from the solutions presented in the accompanying drawings and description, and all of them still fall within the scope of the claims of this application.

Claims

1. A method for obtaining a three-dimensional volume from two-dimensional seismic reflection data by meshing, characterized in that: The latitude and longitude coordinates of each discrete reflection data point are obtained and converted into UTM projected rectangular coordinates to determine the coordinates of the point with the minimum longitude. The optimal azimuth of the grid is calculated based on the planar distribution characteristics of the discrete points, and the grid spacing along the azimuth direction and perpendicular to the azimuth direction is determined. The grid is rotated to the 3D grid direction, and the coordinates of the point with the minimum longitude value are extended outward by half a grid spacing, using the coordinates of this point as the base point of the grid. All coordinate points are rotated in the same way, and the data falling into the same grid are superimposed. Then, the coordinate number of each point in the grid is calculated to obtain the 3D data volume. The implementation steps include the following: Step (1): Determine the projection zone and the longitude of the central meridian based on the latitude and longitude coordinates of the reflection points within the work area; Step (2): Calculate the UTM projection coordinates of the reflection points of each two-dimensional survey line using coordinate projection; Step (3): Calculate and determine the azimuth angle of each two-dimensional survey line based on the UTM projection coordinates; The average azimuth of all two-dimensional survey lines that is less than or equal to the median of the azimuth variance is taken as the azimuth of the two-dimensional grid. Step (4): Calculate the azimuth angle of the two-dimensional grid; First, calculate the average value of the original azimuth angle for each survey line. : (4) Then, calculate the variance of the azimuth angle. : (5) Step (5): Rotate the survey line from the azimuth of the two-dimensional grid to the azimuth of the three-dimensional grid using coordinate rotation; Step (6): Determine the parameters of the three-dimensional data volume observation system; UTM projection coordinates of all reflection points Perform a coordinate rotation, the rotation angle being the azimuth angle of the 3D mesh. To obtain the rotated coordinates : (6) (7) in,( , () is the minimum longitude coordinate () , The projected coordinates after projection transformation. and These represent the desired 3D grid spacing for the output; Step (7): Data overlay within the same 3D grid; Step (8): Calculate the 3D mesh number of all reflection points; Based on the relationship between the coordinates of the reflection points after superposition and the coordinates of the mesh origin, calculate the coordinate number of each reflection point in the 3D mesh. : (9) (10) Step (9): Sort the coordinates of all reflection points after superposition according to the grid number to obtain a three-dimensional meshed three-dimensional data volume.

2. The method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data according to claim 1, characterized in that: In step (1), input two-dimensional seismic reflection data located in the work area. The data includes track heads, survey line spacing and track spacing. The track heads contain spatial coordinate information of the reflection points. Obtain the latitude and longitude coordinates of all two-dimensional survey lines. ,in Determine the minimum longitude coordinates Add 180 to this value, divide by 6, round down, and add 1 to obtain the longitude of the central meridian in the coordinate projection. : (1)。 3. The method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data according to claim 1, characterized in that: Step (2) involves converting the latitude and longitude coordinates of all reflection points into UTM projection coordinates. , ; If the latitude value of the UTM projection coordinates is less than zero, then the work area is located in the Southern Hemisphere, and its latitude value calculation result needs to be increased by 10,000,000; otherwise, the work area is located in the Northern Hemisphere.

4. The method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data according to claim 1, characterized in that: The steps (3) include fitting the original azimuth angle of each two-dimensional survey line using the least squares principle, calculating the variance of the azimuth angle and sorting it from smallest to largest, determining the median of the azimuth angle variance, and selecting the average value of the azimuth angles with variance less than or equal to the median as the azimuth angle of the two-dimensional grid to avoid interference from data with large azimuth angle offsets. Based on UTM projection coordinates The original azimuth angle of each two-dimensional survey line is fitted using the least squares principle. The azimuth angle calculation process is as follows: Step (3.1): Calculate all and and and ; Step (3.2): Calculate all and and and ; Step (3.3): Calculate the slope of the line. : (2) Step (3.4): Calculate the azimuth angle : (3) in, .

5. The method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data according to claim 1, characterized in that: Step (5) includes sorting the azimuth variances of each survey line from smallest to largest, and selecting the average azimuth variances of the top 50% as the azimuth variances of the three-dimensional grid. ; When the survey line is oriented northwest-southeast Take the positive value, when the direction is southwest to northeast. Take the negative value.

6. The method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data according to claim 1, characterized in that: Step (7) includes calculating the origin of the three-dimensional mesh and determining the desired output three-dimensional mesh spacing. and The minimum longitude coordinates ( , Projected coordinates after projection transformation , Expand outward by half and The origin of the three-dimensional mesh is taken as the first one. ; Among them, when When the value is positive, the origin of the 3D mesh is taken as... Conversely, the origin of the 3D mesh is taken as... ; The data falling into each 3D grid is checked. If there are multiple data in a grid, these data are superimposed. The superimposed result is used as the data of the grid center point. The coordinates of the superimposed result are taken as the coordinates of the grid center point. Assume the first Within each grid The data point, the first The values ​​of the data points are Then the data within that grid The value is: (8)。 7. The method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data according to claim 1, characterized in that: In step (9), the parameters of the three-dimensional data volume observation system include the coordinates of the corner points of the work area, the spacing between the main survey lines, the spacing between the connecting survey lines, and the track spacing.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, it implements the method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data as described in any one of claims 1 to 7.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed, it can implement the method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data as described in any one of claims 1 to 7.

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